Loop-taker-operating means for sewing-machines.



G. WINKEL. LOOP TAKBR OPERATING MEANS FOR SEWING MACHINES.

APPLICATION FILED JAN. 18, 1904. Lmmm I Patented Feb. 9, 1915.

2 SHEETS-SHEET 1.

C. WINKEL.

LOOP TAKER OPERATING MEANS FOR SEWING MACHINES.

APPLICATION FILED JAN. 19, 1904.

Patented F811. 9, 1915.

2 sums-5mm 2.

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CHRISTOPHER WINKEL, 0F BELVIDER-E, ILLINOIS, ASSIGNOR TO NATIONAL SEWING MACHINE (10., OF BELVIDERE, ILLINOIS, A CORPORATION OF ILLINOIS.

LOOTP-TAKER-OPERA'IING MEANS FOR SEWING-MACHINES.

Application filed January 18, 1904.

To all whom it may concern.

Be it known that I, CHRISTOPHER VVINKEL, a citizen of the United States, residing at .Belvidere, in the county of Boone and State of Illinois, have invented certain new and useful Improvements in Loop-Taker-Operating Means for Sewing-h/Iachines, of which the following is a full, clear, and exact specification.

My invention relates to that class of sewing machines in which the stitch is produced by the action of a revolvlng or rotating member, which may be either a revolving shuttle or a rotating hook serving as a loop-taker for engaging the loop as it is thrown out by the needle, in the lock stitch form of machine carrying it around the supply of lower thread while in the chain stitch simply pulling it downward and then shedding it to produce the chain in a well known manner, and my improvements are more especially concerned with the means for operating this member and imparting thereto the differential speed of rotation essential in this class of machines.

It is well known that the speed of rotation should be rapid in the maximum degree as soon as possible after the point of the loop-taker or said rotating members enters the loop, and it should be slow in the extreme while the loop is being pulled upward therefrom in the act of completing the stitch. Heretofore it has been proposed to impart this differential speed of rotation wholly to the shaft which drives the looptaker or said rotary member, by means of a wrist pin moving in an oval path engaging a slotted crank arm on said shaft, but it is obvious that to produce the very high speed necessary or desirable the wrist pin must at one point in its line of travel come so close to the center of rotation of the crank as to subject the parts to great strain and offer undue resistance to the driving power.

The primary object of this invention, therefore, is to provide improved and efficient means whereby these extremes of the differential speed may be obtained without causing the wrist to approach too near to the center of rotation of the shaft.

With these ends in view my invention consists in certain features of novelty in the construction, combination and arrangement of parts by which the said objects and cer- Specification of Letters Patent.

Patented Feb. 9, 1915.

Serial No. 189,397.

tain other objects hereinafter appearing are attained, all as fully described with reference to the accompanying drawings and more particularly pointed out in the claims. In the said drawings-Figure 1 is a bottom plan. of a portion of a sewing machine head provided with my improved driving mechanism. Fig. 2 is an enlarged detail view of the loop taker and bearing therefor and with the operating shaft in section. Fig. 3 is a detail cross section on the line 33, Fig. 1, showing the parts right side up. F ig. 4. is a detail cross section of the hook and its supporting mechanism, also showing the means of operatively connecting the hook to the driving shaft, and Fig. is a diagrammatic view looking from the hook or shuttle end of the shaft, showing the orbits or paths in which the principal elements travel. Fig. 6 is a diagrammatic view showing the needle throwing out the loop and the hook in the act of taking the loop. Fig. 7 is a diagrammatic view illusitrating the hook having taken the loop about half way around and the needle having withdrawn.- Fig. 8 is a diagrammatic view illustrating the needle about to pull the loop from the hook in the act of completing the stitch. The principle of operation of the invention may be best understood from Fig. 5. 1 is the shaft, on the ends of which are secured respectively two crank arms 2, 3, which, in this eXemplification-of the invention, are shown as set opposite each other, that is, one 180 degrees in advance of the other. i is a rod or arm which carries at its lower end a wrist pin, or other suitable device, 5 engaging with the crank arm Q in such a way as to impart rotary movement to the shaft 1 through the agency of the crank arm 2. There are various expedients employed in this art for so operating the rod =1 as to cause the wrist pin 5 to travel in a non-circular orbit, and some of these expedients are capable of causing the wrist 5 to travel in an oval or egg-shaped orbit, as indicated by the dotted line 6, such for example as the device shown in U. S. Patent No. 34,610 January 23rd, 1891, and that form may be employed in connection with this invention, and by means of the same it will be seen that when the wrist is passing around the lower concentric side of its orbit,

that is the larger end of the oval which is concentric with the shaft 1, it will impart one-half of a revolution to the crank 2 and the other half of the revolution will not be completed until the wrist shall have passed entirely around the elongated end of the oval. Consequently the first described half of the revolution of the pin 5 will produce a very rapid movement of the crank 2 and shaft 1, but owing to the greater time con sumed in the latter half of its travel, the remaining half o'fthe revolution of the crank 2 and shaft 1 will be comparatively slow audit will be understood that the closer the wrist 5 approaches the center of the shaft 1 during its concentric i'n'ovenient with relation to the shaft the wider will be the difference between these extremes of speed. Heretofo're it has been proposed to employ means similar to this just described for entirely accomplishing the degree, of difference necessary in the two extremes of speed, but it is found in practice that the great ex: tremes cannot be obtained without bringing the wrist 5so' close to the center of the shaft 1 as tocaufse great friction and undue resistance to thfe'power which drives the wrist 5, and consequently this invention contemplates means supplementary to the means described for multiplying or intensifying these extremes of speed without bringing the wrist 5 any closer to the center of shaft 1 than would be consistent with good mechanical construction.

' As a means of operatively connecting the wrist 5 withthe crank 2 the crank maybe provided in its outer face with a longitudinal slot 7 in which the wrist travels and as a means of connecting the crank 3 with the hook or loop-taker this crank is also providedf wi'th a longitudinal slot 8 in which engages a crank pin 9 secured in any suitable way to the hook or loop-taker or to any mechanism connected therewith, which, of course, should be journaled' independently of the shaft 1, and according to this invention is not only journaled' independently of said shaft but its axis of rotation is eccentric to the shaft, so that the line of travel or orbit of the" crank- 9 will be eccentric to the shaft, as indicated by the dotted line 10 in Fig. 5.

11 is a diagrammatic illustration of the point of the hook, shuttle or other looptaker and the circle 12 represents the line of travel of said loop-taker as it is revolved by the crank 3 and crank pin 9. The center or axis of rotation of the hook 11, however, is so disposed with relation to the orbit 6 and shaft 1 that the crank pin 9 will travel through that half of its orbit which is closest to the center of shaft 1 while the wrist 5 is traveling around the elongated half of its orbit 6', and consequently at this time the slow movement of the wrist 5 will be intensified in the motion of the hook 11 by the reduction of speed due to the near proximity of the crank pin 9 to the center of shaft 1. During this half of the rotation the hook 11 is traveling from a point at the lower side of its path at or about the point where the loop starts to draw up or pull away from the hook and the speed of the hook continues to decrease from this point down to the minimum speed where the loop is entirely withdrawn from the hook, the hook l1 turning to the left, or in a direction away from the operator in this example of the invention. During the remaining half of the revolution of the hook, the hook is passing through the new loop thrown out by the needle as usual and taking the loop downward toward the left, and, if employed in connection with a lock stitch form of machine, carries the loop around the supply of lower thread in the usual way to the point at the under side where the loop begins to pull away from the hook, as before described. During this rapid half of the revolution the wrist 5 will be passing in the direction of the arrows in Fig. 5 around the under side of its oval path of travel in its closest relation to the center of shaft 1, but the crank pin 9 at this time will be at the outer end of the slot 8 at its farthest distance from the center of the shaft 1 in the orbit 10 of its travel, and consequently will be revolving the hook 11 at the increased rate of speed due to the increased distance between the crank pin 9 and the shaft 1 as multiplied or intensified by the near-proximity of the wrist 5 to said shaft 1. a means of thus journaling the hook or rotary loop-taker 11 eccentric to the shaft 1 the body portion 13 of the hook or rotary loop-taker is formed with a neck or ournal 1a and this is mounted in a ring 15 which constitutes the journal bearing therefor, and it is held against longitudinal endwise movement in the ring 15 by a flange 16 detachably secured to the end of the journal 14 and overlapping the back of ring 15, and this flange 16, which is also in the form of a ring, forms a means for the attachment of the crank pin 9 which is engaged by the slotted crank 3, as before described. The ring 15, so far as this invention is concerned, may constitute a part of any suitable support for securing the same to the sewing machine head plate 17, such, for example,

as a ring 18 having bosses 19 secured to the bottom of the plate or base 17 in any suitable way, the crank pin 9 and slotted crank 3 being situated within the ring 18, as shown in Fig. 4. In the drawings the ring 15 is shown as a separate piece from the ring 18 as a feature in the method of construction, but this particular form of hook and manner of journaling it constitute the subjectmatter of the claims in my pending application Serial No. 185,976, filed Dec.

names 21st, 1903, and need not be further dwelt upon in this application, which concerns itself primarily with the driving mechanism, and simply requires that the rotary loop-taker be of such a character that it may be journaled independently of the shaft.

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent is:

1. In a rotary sewing machine, the combination of a shaft having a crank arm at each end and each crank arm having a slot therein radiating from the shaft; a wrist pin engaging one of said slots and adapted to impart rotary movement to the shaft at speeds varying during each rotation; a rotary loop-taker having its axis eccentric to said shaft; and a Wrist pin carried by said loop-taker, engaging the other of said slots forming an operative connection between said last mentioned slot and said loop-taker and adapted to vary the relative rotary movement of the loop-taker and shaft in each rotation thereof.

2. In a loop taker operating mechanism for sewing machines, the combination of a revolving loop taker, a journal bearing for said loop taker consisting of a ring through which a part of the loop taker projects, a member adjacent the side of the ring opposite the loop taker and secured to the said part, said member being provided with a wrist pin, a shaft arranged eccentric to the loop taker, a slotted crank on said shaft in which the wrist pin is adapted to move, a second crank on said shaft set opposite to the first said crank, and means moving in a non circular orbit projecting into and movable in the slot in the said second crank for rotating said shaft.

CHRISTOPHER WINKEL.

Witnesses:

WILLIS S. BROWN, JOHN W. ELDREDGE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

